1. Field of the Invention
The invention relates to a portable hand-held phase-shift detector capable of interfacing with piezoelectric microcantilever sensors (PEMS) and methods for using the detector and a system including the detector. The invention is particularly useful as a sensor or diagnostic device.
2. Description of the Related Technology
Biosensors and chemical sensors coupled with impedance analyzers are well known in the art. For example, U.S. Pat. No. 6,278,379 and U.S. publication nos. 20060257286 and 20060217893 discloses sensor systems incorporating an impedance analyzer to detect changes in resonance frequency.
Current impedance analyzers, however, are typically bulky, heavy and relatively immobile, thereby limiting the circumstances in which resonance frequency may be measured. Although some impedance analyzers, such as impedance analyzers for determining the physical properties of large structures such as a building and impedance analyzers for determining body composition have been made portable, as disclosed by U.S. patent application publication no. 2005/0114045 and U.S. Pat. No. 6,280,396, impedance analyzers for use with chemical sensors or biosensors remain large, cumbersome and relatively immobile.
Therefore there is a need to develop a light, portable, hand-held detector to facilitate diagnostic or sensor applications.